Natural selection past the reproductive age

Discussion in 'Biology & Genetics' started by spuriousmonkey, May 17, 2004.

  1. John Connellan Valued Senior Member

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    Nah I HAVE learnt some ecology already in my time.

    An example would be a mother feeding her offspring milk. There is absolutely no net benefit to the individual here.
     
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  3. paulsamuel Registered Senior Member

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    Specifically, Chapters 11-14 in the second edition."
     
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  5. paulsamuel Registered Senior Member

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    I'm not even going to embarass you by responding to that. I suggest you delete it.
     
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  7. John Connellan Valued Senior Member

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    I won't be embarassed please! Im sure u are quite an expert in this field so I want to hear your views!
     
  8. Buckaroo Banzai Mentat Registered Senior Member

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    At least to me, all these altruistic stuff stays clear when you think about the genetic spread, forgetting momentarily individuals as any other thing than a tool for genetic spread....
     
  9. spuriousmonkey Banned Banned

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    This reminds me of the thoughts on the evolution of human fetus size.

    For a fetus it is better if it is bigger when it is born.

    For the mother there are more risks involved (for instance during pregnancy) when the fetus grows larger.

    Both are in a 'struggle' to dominate their our interests. This results in a certain fetus size which is not necessarily optimal for the mother or the fetus.
     
  10. John Connellan Valued Senior Member

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    Exactly. That is all individuals are.
     
  11. spuriousmonkey Banned Banned

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    I wonder if anyone researched these agressive tendencies. Is this just an observation or is it a significant behavioural pattern?
     
  12. BigBlueHead Great Tealnoggin! Registered Senior Member

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    John: If a mother is 50% related to her child genetically, then the "feed your child" allele would not be expressed as an altruistic trait, would it? Feeding your child would be helping your genetic material (some of it, anyway) to continue to survive.

    Hence, altruistic acts in nature are difficult to find. That's why I had to resort to the pitcher plant example, which by the way I still cannot find a reference for.

    EDIT: I mean TRUE altruism, that is, with no measurable benefit to the agent.
     
    Last edited: May 19, 2004
  13. paulsamuel Registered Senior Member

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    In nature there are four types of altruism which all involve mutal benefits.

    1) Inclusive fitness (aka kin selection).
    2) mutualism
    3) manipulation
    4) reciprocity

    AFAIK, there are no examples of altruism in the wild that do not fit into these four categories.
     
  14. Buckaroo Banzai Mentat Registered Senior Member

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    I think that there's no behavior that isn't genetically selfish... allways that something looks altruistic is somehow helping genes of relatives to pass (in the gene perspective, he's just helping himself to pass, no matter in which bodies he's in), and when isn't a relative being helped, it's increasing the agent's own fitness in a situation that he's likely to be repaid.
     
  15. John Connellan Valued Senior Member

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    Of course it is. There is no measurable benefit to the individual there.

    Im afraid because of the selfishness of genes, altruistic effects are bountiful in nature.

    If u want to call an altruistic act which does not benefit the genes "true altruism" then go ahead. The actual definition involves the individual.
     
  16. John Connellan Valued Senior Member

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    No. Kin selection does not bestow ANY benefits on an individual unless it includes reciprocity but u have mentioned that already.
     
  17. spuriousmonkey Banned Banned

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    Nobody really went deeper into the matter than just stating 'altruism'.


    a bit disappointing.
     
  18. paulsamuel Registered Senior Member

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    Your language is a bit imprecise.

    Biological science contends that kin selection is a means by which apparent altruistic traits can evolve and be maintained in a population.

    If you wish to take a position on kin selection and altruism in opposition to biological science, then you should probably state your opposition a bit more clearly and include examples from biological experiments.

    Otherwise you sound a bit puerile.

    If you wish to know why biological science contends this, then you should probably read the reference which I have provided.
     
  19. paulsamuel Registered Senior Member

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    Well there is evidence that cetaceans will help individuals in their group who are beyond reproductive age. These older individuals have been observed aiding the rearing of young. The theory is that inclusive fitness allows these apparent altruistic traits to evolve.

    There is also evidence that non-reproductive males in red-winged blackbird populations are tolerated in breeding males' territories for the same reason.

    Is that better?
     
  20. John Connellan Valued Senior Member

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    Why isn't it right to say that inclusive fitness allows these altruistic traits to evolve, rather than "apparent altruistic"? I've always been taught that Kin selection explained altruism

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  21. BigBlueHead Great Tealnoggin! Registered Senior Member

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    Why are they apparently altruistic when you know about the selfish gene theory? Do you refer to a speeding Buick as "soft" because it has leather seats? I agree with spurious that we've got a failure of definition here.

    We can pretty confidently assert that propagation of your genetic material is of benefit to you. Since inclusive fitness theorizes that helping your offspring and their offspring and so on, we can consider the propagation of your offspring's genetic material to be of benefit to you, and hence aiding this is not altruistic. Much as Dr. Lou says, it is not even apparently altruistic because everyone else knows exactly what you're doing.

    A truly altruistic action would then be one that
    1) Did not improve your personal fitness
    2) Did not preferentially aid the transmission of your genetic material

    In the sense of (2), an allele that coded for a truly altruistic would never become fixed in a population.

    Examples of truly altruistic behaviour:
    A) Suicide - since the increase in individual fitness for all of your conspecifics will be about equal, a suicidal gene that does not have some other inherent act (such as defending the hive) could be considered truly altruistic since it does not specifically aid your relatives.
    B) Pathological behaviour caused by parasites - some parasites, such as everyone's favourite Leucochloridium snail parasite, can change the behaviour of their host. In the case of the aforementioned snail fluke, they make the snail seek out sunny places so that they can be eaten by birds. Now, this is a case where the parasite has evolved to take advantage of a weakness in the snail's physiology, but the snail's behaviour can still be considered altruistic by the criteria of (1) and (2).
     
  22. John Connellan Valued Senior Member

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    They aren't. They ARE altruistic. I think u mixed your sentence up!

    I think its more a disagreement of definition

    I disagree.

    I disagree.

    I'm sure only the human species knows about it

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    YES. And there are a lot of things in the wild which do not improve personal fitness and in fact lower it (altruism).

    No, I'm afraid I don't believe this should be considered in the definition of altruism scientifically.

    Exactly so that definition of altruism should not exist.
     
  23. John Connellan Valued Senior Member

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    I disagree. I was taught that is a means by which ALTRUISTIC traits can evolve. The reason I am arguing it so much is because I feel it is a better definition.

    I have no idea what u are thinking here. Experiments? I am not opposing biological science as such (I think!)

    What did I say that sounded puerile?

    I'll have to get round to reading some text alright to find out what altruism really is nowadays!
     

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